[14C]Senecionine production in Senecio vulgaris root culture.

This chapter describes the growth of root cultures from S. vulgaris, the production of pyrrolizidine alkaloid (PA) and the specific labelling of the compound in these cultures. Ideally, a final tissue mass of ~4 g is required for extraction and further processing. To obtain this, growth from a 200 to 250 mg stock for ~10 days is required. During this period, the culture is producing unlabelled senecionine, which will 'dilute' labelled alkaloid produced during a 24 h labelling period. If extremely 'hot' alkaloids is required for a specific purpose, it is suggested that roots be 'grown up' in an IBA-containing medium, promoting rapid root growth but little senecione production, and then placed in IBA-free medium for labelling. In this way, an even higher specific activity should be obtained. The manufacture of specifically labelled natural products in plant tissue culture in general, and roots in particular, will prove to be a very useful technique in toxic plant research.